U.S. Pat. No. 4,186,239 discloses a cutting filament made of nylon and having a substantially round or elliptical cross section. The filament has a plurality of notches extending transversely to the longitudinal axis and arranged on the surface. In addition, this patent describes cutting filaments which consist of two or more filament bodies, which are joined to each other along their longitudinal axis or are combined to form a star-shaped profile. These configurations of cutting filaments all have a cross section with point symmetry, either the point symmetry being provided at 90.degree., such as for example in the case of a cross-shaped cross section, or at 180.degree. as in the case of an elliptical cross section. In the known star-shaped profiles, the base body has a small cross section which causes the strength of the cutting filament to be relatively low. The notches extending transversely with respect to the longitudinal axis are intended to prevent the nylon filament from fraying; that is, the notches define predetermined breaking edges at the free end of the cutting filament.
European patent publication 0,260,158 likewise discloses a cutting filament having a star-shaped cross section so that this cutting filament also has point symmetry.
The noise level of vegetation cutters is very high because apparatus of this type are operated at high rotational speeds of up to 10,000/min. This noise level is caused primarily by the shedding of vortices on the cutting filament rotating at high speed.